The objective of this research is to extend a recently developed Quasiparticle self-consistent GW method (QSGW) to study quantum transport in molecular and nanoscale devices. Because QSGW is very accurate, it is uniquely situated as a framework around which a reliable ab initio theory can be constructed. The full QSGW theory, however, is too expensive to be a practical engine for device design?at least as originally implemented. The major focus of this work will threefold first, to redesign a real-space version of QSGW theory, that should execute far more efficiently than the standard implementation with essentially the same reliability; second to design physically sound approximations to QSGW that are suitable for larger-scale applications, such as transport graphene, and new metal/insulator/metal spintronic designs. Intellectual Merit: It is a significant accomplishment to develop an accurate, universal method which can predict many properties for a wide variety of systems in a unified way. This proposal extends QSGW in two directions: to calculate quantities of importance to quantum transport, e.g. phonons, the electron-phonon interaction, Auger recombination, and to find simplifications to enable practical study of many interesting materials problems. Broader Impact: This work can significantly extend both the type of materials properties, the precision to which they can be calculated, and the complexity of the materials systems accessible. It lays the groundwork to enable realistic prediction of the performance of several future generations of electron devices. 1
A new and improved approach has been developed to theoretically calculate the properties of solids. This method, called the quasiparticle self-consistent GW (QSGW) technique, is able to more precisely model the interactions between electrons in solids so that the predictions are more precise, up to a factor of greater than 10 times in accuracy. Electrons are responsible for forming the chemical bonds that bind solids together and the transport of electrical conduction. This advance in improving the understanding of the electron properties is extremely important because it enables scientists to reliably forecast which materials are best for a certain application, saving the time and expense of the laborious and expensive trial-and-error methods of fabricating and testing new materials in the lab. The results of the calculations can be used to predict the optical, electrical, thermal, structural and magnetic parameters that are needed to design the next generation of advanced technologies. The publications generated by this grant have described the steps necessary to use this method and a large number of groups have started using the GSGW method for both practical and scientific research. The QSGW technique has already proven to be extremely valuable in guiding scientists in new directions for the next generation of materials used in hard-drives, ultra-fast computer logic and large area photovoltaic applications.
